The management of workload plays an important role in computing environments today. Thus, various aspects of processing within a computing environment are scrutinized to ensure a proper allocation of resources and to determine whether any constraints exist. One type of processing that is scrutinized is I/O processing.
In I/O processing, workload management includes properly allocating different kinds of channels to control units. To determine whether the allocation is sufficient, channel delay is measured. Previously, the metric of channel delay included measuring the response times. In application Ser. No. 09/676,715, “Method, System and Program Products for Projecting the Impact of Configuration Changes on Controllers,” Johnson et al., previously incorporated herein by reference, the metric used is channel pending time.
When it is determined that the allocation is insufficient, then various changes need to be made. The cost of making these changes is expensive and thus, a need exists for a technique for projecting the impact of configuration changes on the control units, prior to making the adjustments. In particular, a need exists for a capability that quantifies the impact of a change on one or more control units to be affected by that change.
Furthermore, I/O configurations exist where one or more channels are connected, either directly or indirectly, to a bridge device. Such a channel is referred to as being bridge attached. A bridge device may perform either or both of the following functions. First, a bridge device may perform protocol conversion, allowing a device using one protocol to communicate with a device using a different protocol. Second, a bridge device may perform capacity matching, providing a mechanism for communicating the information from two or more low capacity links over a single high capacity link. In computing environments having one or more bridge attached channels, a further need exists for projecting the impact of configuration changes which takes into account the capabilities of bridge attached channels.